JP3608036B2 - Moisture curable urethane resin composition and waterproof material - Google Patents

Description

備考：ルプラネートＭＩ：４，４’−ジフェニルメタンジイソシアネートと２，４’−ジフェニルメタンジイソシアネートの１：１の混合物、ＮＣＯ％＝３３．７％（ビーエーエスエフジャパン製）
イソネート１４３Ｌ ：カルボジイミド変性ＭＤＩ、ＮＣＯ％＝２９．４％（ダウポリウレタン日本製）
ＮＣＯ／（Ｈ） ：化合物（Ａ）と（Ｂ）のＮＣＯ当量の和と化合物（Ｃ）が解離したときに発生する活性水素の当量の比を示す。
【００４９】
【表２】
［配合条件及び試験結果］

備考：２，４−ＴＤＩは２，４トリレンジイソシアネートを意味する。
【００５０】
【表３】
［配合条件及び試験結果］

【００５１】
比較例１の（Ｂ）成分を含まない組成物及びは残存タックが大きい結果となった。比較例２は実施例１のルプラネートＭＩに相当するＮＣＯ当量の２，４−ＴＤＩを加えたものであるが、実施例１に比較して残存タックが大きい結果となった。比較例３は化合物（Ｂ）を請求範囲よりも多く入れたものであり、残存タックは良好なものの防水材としての破断伸度が低く勝つ貯蔵後の粘度上昇が大きいものであった。比較例５は化合物（Ｂ）を請求範囲より少なく入れたもので残存タックが大きい結果となった。比較例５、６はＡ成分においてトリレンジイソシアネートの代わりに４，４’−ジフェニルメタンジイソシアネートを用いたものであり、比較例６は残存タックが少ないもののいずれも粘度が高く塗布作業性が悪いと予想される上に貯蔵後の粘度上昇が大きいものであった。
【００５２】
【発明の効果】
本発明は、硬化時に炭酸ガスによる発泡がなく、硬化性、貯蔵安定性に優れる湿気硬化性ウレタン樹脂組成物であり、更に塗膜表面の残存タックが少ないという特徴を持つ湿気硬化性ウレタン樹脂組成物及びそれを用いた防水材である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moisture curable urethane resin composition that is free from foaming due to carbon dioxide gas at the time of curing, has excellent curability and storage stability, and has little residual tack on the coating film surface, and a waterproof material using the same.
[0002]
[Prior art]
As a conventional moisture curable urethane resin composition, JP-A-57-94056 is known, but often swells due to carbon dioxide gas generated when moisture and isocyanate groups react during curing. There is a problem that occurs. Moisture dissociation type crosslinking agents such as ketimine and enamine have been proposed in order to suppress the generation of carbon dioxide which causes blistering. Among them, JP-A-6-293821, JP-A-7-33852, JP-A-Hei. A composition using an oxazolidine compound proposed in Japanese Patent Application Laid-Open No. 7-10949 is a material that does not generate carbon dioxide and has a relatively balanced performance.
[0003]
However, in the coating film in which the oxazolidine group is ring-opened by moisture to generate active hydrogen and reacts with the urethane prepolymer, as shown in JP-A-6-293821, the surface has a large residual tack. When walking on the membrane, there was a problem that there was a sticky feeling and dirt easily adhered. Furthermore, due to the recent trend of shortening the construction period, there is a demand for a material that often walks on the surface of the coating one day after the construction and that reduces tack in a short period of time.
[0004]
[Problems to be solved by the invention]
An object of the present invention is a moisture-curable urethane resin composition that is free from foaming by carbon dioxide gas at the time of curing and has excellent curability, and further has a feature that there is little residual tack on the surface of the coating film and There is a waterproof material using it.
[0005]
[Means for Solving the Problems]
As a result of intensive studies on the above problems, the present inventors have completed the present invention.
[0006]
That is, the present invention includes (A) a urethane prepolymer having two or more isocyanate groups at the terminal consisting of a reaction product of tolylene diisocyanate and polyoxyalkylene polyol, (B) polyphenylmethane polyisocyanate or a carbodiimide modified product thereof, C) (c1) a urethane prepolymer having two or more isocyanate groups at the terminal, and (c2) a urethane oxazolidine prepolymer having an oxazolidine group at the terminal obtained by reacting N-2-hydroxyalkyloxazolidine, Moisture curable urethane resin composition, preferably polyphenylmethane polyisocyanate or its carbodiimide modified product (B), wherein the isocyanate equivalent ratio of A) and (B) is 90:10 to 15:85, 4,4'-diphenylmethane It is a mixture of diisocyanate and 2,4′-diphenylmethane diisocyanate or carbodiimide-modified diphenylmethane diisocyanate, and provides a waterproof material comprising the same.
[0007]
The present invention is further described below.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The urethane prepolymer (A) having two or more isocyanate groups at the terminal consisting of a reaction product of tolylene diisocyanate and polyoxyalkylene polyol used in the present invention is obtained by adding tolylene diisocyanate and polyoxyalkylene polyol under an excess of isocyanate. And a prepolymer prepared by a conventional method.
[0009]
The polyoxyalkylene polyol used here is ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, glucose, sorbitol, one or more polyhydric alcohols such as sucrose, and propylene oxide. And polyols obtained by adding one or more of ethylene oxide, butylene oxide, styrene oxide, and the like, and polyoxytetramethylene polyol.
[0010]
The urethane prepolymer (c1) having two or more isocyanate groups at the terminal is a urethane prepolymer prepared by an organic polyisocyanate and a polyol in the same manner as the compound (A) under an excess of polyisocyanate.
[0011]
Organic polyisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, partially carbodiimidized diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, tolylene diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene. Examples thereof include aromatic diisocyanates such as diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and cyclohexane diisocyanate, aliphatic diisocyanates, and alicyclic diisocyanates.
[0012]
Moreover, this polyol is polyether polyol, polyester polyol, other polyols, and these mixed polyols. For example, a polyol produced using a double metal cyanide complex as a catalyst is also included.
[0013]
Examples of polyether polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, glucose, sorbitol, and one or more polyhydric alcohols such as sucrose, propylene oxide, ethylene oxide, butylene. Examples thereof include polyols obtained by adding one or more of oxides, styrene oxides, and the like, and polyoxytetramethylene polyols.
[0014]
Examples of the polyester polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, trimethylolpropane, and one or more other low molecular polyols, glutaric acid, adipic acid, Pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, hydrogenated dimer acid or other low-molecular dicarboxylic acids or oligomers with one or more condensation polymers, propiolactone, caprolactone And ring-opening polymers such as valerolactone.
[0015]
Examples of other polyols include polycarbonate polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, and acrylic polyol. In addition, low molecular polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol glycerin, trimethylolpropane, glucose, sorbitol, and shoelace.
[0016]
The polyol of the component (A) is preferably a polyether polyol having a number average molecular weight of 500 to 16000 and preferably not containing an oxyethylene chain. More preferred are polyether diol and / or polyether triol. When a polyol containing an oxyethylene chain is used as the component (A), the amount of the oxyethylene chain in the component (C) is calculated, and the content of the oxyethylene chain in the composition is that of the components (A) and (C). The amount is preferably less than 6% by weight based on the total amount.
[0017]
The number of terminal isocyanate groups in the urethane prepolymer (A) is preferably 2 or more, more preferably 2 to 3. Furthermore, the NCO / OH ratio of isocyanate and polyol is preferably 1.4 or more, more preferably 1.4 to 5.0. The residual NCO% is preferably 1 to 20% by weight.
[0018]
Polyphenylmethane polyisocyanate or its modified product (B) is, for example, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified MDI, commercially available products Millionate MR-100, MR-200 (Japan) Crude MDI known under a trade name such as Polyurethane Co., Ltd. is used alone or in combination, and in particular, a mixture of 4,4′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate and carbodiimide-modified diphenylmethane diisocyanate are preferably used. .
[0019]
The ratio of the prepolymer (A) having two or more isocyanate groups at the terminal of the present invention to polyphenylmethane polyisocyanate or a modified product (B) thereof is an isocyanate (NCO) equivalent ratio of 90:10 to 15:85. The ratio is more preferably in the range of 85:15 to 50:50. When the ratio of the component (B) is less than 10 (the component (A) is more than 90), there is no effect of reducing the residual tack, and when it is more than 85 (the component (A) is less than 15), JIS A sufficient value cannot be obtained with the elongation at break specified in -A-6021, and the increase in viscosity after storage becomes large.
[0020]
The polyol of the urethane prepolymer (c1) of the urethane oxazolidine prepolymer (C) preferably has an oxyethylene chain. However, even a polyol obtained by mixing a polyol having no oxyethylene chain and a polyol having an oxyethylene chain can be used as the component (c1). The average content of oxyethylene chains in the oxyalkylene chain is preferably 1 to 30% by weight. If the oxyethylene chain content is less than 1% by weight, the curing rate decreases, and if it exceeds 30% by weight, further improvement in curability cannot be expected, and the water resistance tends to decrease. However, the oxyethylene chain amount of the (A) component and the (C) component is calculated and totaled, and the content of the oxyethylene chain is less than 6% by weight with respect to the total amount of the (A) component and the (C) component. It is preferable that Beyond this, the water resistance will be poor.
[0021]
The urethane prepolymer (c1) preferably has a number average molecular weight of 500 to 8000. When the molecular weight is less than 500, there is a problem in the base followability, and when the molecular weight exceeds 8000, there is a problem that the curing rate is lowered. Further, the average number of NCO groups at the end of the urethane prepolymer (c1) is preferably 2.0 to 2.6.
[0022]
If it is less than 2.0, the curability tends to decrease, and if it exceeds 2.6, the ground followability tends to decrease. Furthermore, the NCO / OH ratio of isocyanate and polyol is preferably 1.6 or more, more preferably 1.8 to 4.0. The residual NCO% is preferably 1 to 15% by weight.
[0023]
The reaction ratio between the urethane prepolymer (c1) and the N-2-hydroxyalkyloxazolidine (c2) is preferably NCO / 0H = 0.95 to 3.0. If NCO / 0H is less than 0.95, N-2-hydroxyalkyloxazolidine tends to remain unreacted, which adversely affects storage stability. When NCO / 0H = 3.0 is exceeded, there are problems of a decrease in the curing rate and an increase in the viscosity.
[0024]
The N-2-hydroxyalkyloxazolidine (c2) used for the synthesis of the urethane oxazolidine prepolymer (C) includes, for example, aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, benzaldehyde, and diethanolamine, dipropanolamine, etc. It is a compound obtained by a well-known condensation reaction with dihydroxyalkylamines.
[0025]
The number of terminal oxazolidine groups in the urethane oxazolidine prepolymer (C) is preferably 1 to 3. If it exceeds 3, the extensibility after curing decreases, which is not preferable. still,
Needless to say, if the urethane oxazolidine prepolymer (C) has at least one oxazolidine group at the terminal, the other terminal may be an isocyanate group.
[0026]
The blending ratio of the sum of the prepolymer (A) and the compound (B) and the urethane oxazolidine prepolymer (C) is such that the sum of the NCO groups of the prepolymer (A) and the compound (B) and the prepolymer (C) are opened with water. The ratio to the active hydrogen group generated by ring is preferably in the range of 0.4 to 4.0. If it is larger than 4.0, the coating film tends to swell due to the generation of carbon dioxide gas, and if it is less than 0.4, the storage stability is lowered. Considering such points, the mixing ratio of (A) + (B) and (C) is preferably in the range of 60: 1 to 1:30 by weight.
[0027]
When the composition of the present invention is used in these applications, a known urethane catalyst such as a known oxazolidine ring-opening catalyst such as phosphoric acid or propionic acid, a tertiary amine or dibutyltin dilaurate can be used. It may also contain various additives such as solvents, inorganic fillers, small amounts of process oils, plasticizers, thixotropic agents, extender pigments, UV inhibitors for stabilizing and improving weather resistance, and stabilizers as necessary. Good. These mixtures can be produced with a mixing and kneading apparatus sufficient to be able to uniformly mix and ensure storage stability.
[0028]
As the solvents, usual urethane solvents such as toluene, xylene, terpene, and ethyl acetate can be used.
[0029]
Examples of the thixotropic agent include surface-treated calcium carbonate, polyvinyl chloride powder, fine powder silica, bentonite and the like. In addition, the composition of the present invention may be mixed with a petroleum-based high-boiling aromatic fraction, petroleum resin, or the like.
[0030]
Examples of the plasticizer include ester plasticizers such as dibutyl phthalate, dioctyl phthalate, diundecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, diisodecyl phthalate, dibutyl adipate, dioctyl adipate, diisodecyl adipate, dioctyl azelate, and dioctyl sebacate. Phosphate ester plasticizers such as trioctyl phosphate and triphenyl phosphate can be mentioned, but if the amount exceeds 12% by weight based on the total composition, the residual tack becomes undesirably large.
[0031]
Examples of the stabilizer include an antioxidant and an ultraviolet absorber. Examples of the inorganic filler include powders of inorganic compounds such as calcium carbonate, calcium oxide, clay, talc, titanium oxide, calcium hydroxide, aluminum sulfate, kaolin, zeolite, clay, and glass balloon. The addition amount is preferably 1 to 70, more preferably 30 to 60% by weight in the composition.
[0032]
The composition of the present invention can be used as a waterproofing material for buildings as a representative application. For example, when used for a waterproofing material for roofing, the organic solvent content of the compound is 12% by weight or less and the viscosity is 18000 cps or less. The organic solvent content is 10 wt% or less and the viscosity is 15000 cps or less / 25 ° C. When used as a waterproofing material, if the content of the organic solvent exceeds 12% by weight, the shrinkage of the coated film after curing is not preferable, and if the viscosity exceeds 18000 cps / 25 ° C., the coating workability is not preferable.
[0033]
【Example】
EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these Examples. In the following, all parts and percentages are based on weight unless otherwise specified.
[0034]
<Synthesis of component (A)>
(Production Example 1 of urethane prepolymer)
Number average molecular weight 2000 polypropylene ether diol 600g, number average molecular weight 5000, polypropylene ether triol 200g, 2,4-tolylene diisocyanate 110g, that is, NCO / OH equivalent ratio 1.76 at 80 ° C under nitrogen stream at 20 ° C. The reaction was conducted with stirring in the flask for a time to obtain a urethane prepolymer (A-1) having an NCO% of 2.52%.
[0035]
(Production example 2 of urethane prepolymer)
1500 g of polyethylene propylene ether diol having a number average molecular weight of 3000 and an oxyethylene chain content of 4% is 174 g of 2,4-tolylene diisocyanate, that is, an NCO / OH equivalent ratio of 2.00 and 20 at 80 ° C. under a nitrogen stream. The reaction was conducted with stirring in the flask for a time to obtain a urethane prepolymer (A-2) having an NCO% of 2.51%.
[0036]
(Production Example 3 of Urethane Prepolymer)
In Preparation Example 1 of urethane prepolymer, 162 g of 4,4′-diphenylmethane diisocyanate was used instead of 110 g of 2,4-tolylene diisocyanate. That is, a urethane prepolymer (P-3) having an NCO% of 2.52% was obtained by stirring in a flask at 80 ° C. for 20 hours under a nitrogen stream at an NCO / OH equivalent ratio of 1.80.
[0037]
<Synthesis of component C>
(Production Example 1 of Urethane Oxazolidine Prepolymer)
20 g of polyethylene propylene ether triol having a number average molecular weight of 600 and oxyethylene chain content of 30% and 270 g of polypropylene ether diol having a number average molecular weight of 600 are mixed to obtain an average content of oxyethylene chain of 2.1% and an average number of functional groups of 2. 07, a polyol having a number average molecular weight of 600 was obtained. Further, 174 g of 2,4-tolylene diisocyanate, that is, a urethane prepolymer having an NCO% of 9.07% by reacting with stirring in a flask at 60 ° C. for 48 hours under a nitrogen stream at an NCO / OH equivalent ratio of 2.0. (B1-1) was obtained.
[0038]
48.7 g of urethane prepolymer (b1-1) and 15.9 g of 2-isopropyl 3 (2hydroxyethyl) 1,3 oxazolidine, that is, an NCO / OH equivalent ratio of 1.05 at 60 ° C. under a nitrogen stream. It was made to react, stirring for a while in a flask, and the urethane oxazolidine prepolymer (OXZ-1) was obtained. As a result of measuring GPC of this composition, it was confirmed that the content of the remaining 2-isopropyl 3 (2hydroxyethyl) 1,3 oxazolidine was 1% or less.
[0039]
(Production Example 1 of Urethane Oxazolidine Prepolymer)
In Preparation Example 1 of urethane oxazolidine prepolymer, 277.5 g of 4,4′-diphenylmethane diisocyanate was used instead of 174 g of 2,4 tolylene diisocyanate. That is, a urethane prepolymer (b1-2) having an NCO% of 9.06% was obtained by stirring in a flask at 60 ° C. for 48 hours under a nitrogen stream at an NCO / OH equivalent ratio of 2.22. Further, urethane oxazolidine prepolymer (OXZ-2) was obtained in the same manner as in Preparation Example 1 of urethane oxazolidine prepolymer.
[0040]
<Compound compounding, applied to Examples 1-4 and Comparative Examples 1-6>
Next, 320 parts of calcium carbonate (NS-200 manufactured by Nitto Flour Chemical Co., Ltd.), which was dried under reduced pressure for 5 hours while stirring at 120 ° C. in a closed biaxial butterfly mixer and adjusted to a moisture content of 0.05% or less, was stirred at 100 ° C. While being dried under reduced pressure for 5 hours, 25 parts of a fatty acid-treated calcium carbonate (manufactured by Maruo Calcium Co., Ltd .: Sealets 200) adjusted to a water content of 0.1% or less, 80 parts of xylene, 80 parts of dioctyl phthalate, acidic phosphate ester AP-3 ( Daihachi Chemical Co., Ltd.) 0.6 parts, urethane prepolymer (A), urethane oxazolidine prepolymer (B) and compound (C) shown in the table below were added in predetermined amounts and mixed uniformly, and then under reduced pressure of 20 Torr. To obtain a moisture-curing urethane compound.
[0041]
[Test method]
(Initial viscosity)
Two days after sample preparation, the sample is stirred for 1 minute with a thermometer, adjusted to 25 ° C., and then the viscosity is measured with a BM rotational viscometer.
[0042]
(Viscosity after storage)
After the sample filled in the sealed container is left in a 50 ° C. dryer for 7 days, the viscosity is measured by the same method as the initial viscosity.
[0043]
(Viscosity ratio)
Calculated as viscosity after storage ÷ initial viscosity.
[0044]
(Curing test)
Enclose the four sides with a frame and pour the sample on a slate plate (30 x 30 cm) at a thickness of 1.4 mm, leave it at 23 ° C x 65%, touch it with your finger, and wait until the coating film does not move Was measured.
[0045]
(Residual tack test)
A sample prepared by the same method as in the curability test was allowed to stand for 24 hours and 7 days at 23 ° C. × 65%, and then carbon paper (2.5 × 2.5 cm) was placed on the surface of the coating film, and the bottom was 2.5 cm. Place a weight of 2.5 cm (500 g) and leave it for 1 minute, and visually observe the carbon stains on the coating surface.
◎, if the carbon contamination is extremely low
○ when there is little dirt
If the stain is but moderate △,
If it is very dirty, it is marked as x.
[0046]
(Non-foaming test)
For non-foaming properties, a sample was poured at a rate of 2 mm on a slate plate (30 × 30 cm) surrounded by a frame on all sides, and cured under conditions of 50 ° C. × 90%. The presence or absence of holes was observed. Those with no blisters and pinholes were marked with ◯, and those with blisters and pinholes were marked with ×.
[0047]
(Tensile property test)
Tensile properties were measured by flowing a sample at a rate of 1.5 mm on a glass plate (30 × 30 cm) surrounded by a frame on all four sides and releasing release paper, and allowed to cure for 14 days under conditions of 23 ° C. × 65%. Thereafter, the tensile strength (kg / cm ² ) and elongation at break (%) were measured using a tensile tester under the condition of a tensile speed of 500 mm / min.
[0048]
[Table 1]
[Composition conditions and test results]

Remarks: Lupranate MI: 1: 1 mixture of 4,4′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate, NCO% = 33.7% (manufactured by BASF Japan)
Isonate 143L: Carbodiimide-modified MDI, NCO% = 29.4% (made by Dow Polyurethane Japan)
NCO / (H): A ratio of the sum of NCO equivalents of the compounds (A) and (B) to the equivalent of active hydrogen generated when the compound (C) is dissociated.
[0049]
[Table 2]
[Composition conditions and test results]

Note: 2,4-TDI means 2,4 tolylene diisocyanate.
[0050]
[Table 3]
[Composition conditions and test results]

[0051]
The composition containing no component (B) in Comparative Example 1 and the residual tack were large. In Comparative Example 2, NCO equivalent of 2,4-TDI corresponding to Lupranate MI of Example 1 was added, but the residual tack was larger than that of Example 1. In Comparative Example 3, the compound (B) was added in a larger amount than the claimed range, and the residual tack was good, but the breaking elongation as a waterproofing material was low and the viscosity increase after storage was large. In Comparative Example 5, the compound (B) was added in less than the claimed range and the residual tack was large. Comparative Examples 5 and 6 are those in which 4,4′-diphenylmethane diisocyanate was used in place of tolylene diisocyanate in the A component, and Comparative Example 6 was expected to have low viscosity and high coating workability, although it had little residual tack. In addition, the increase in viscosity after storage was large.
[0052]
【The invention's effect】
The present invention is a moisture curable urethane resin composition which is free from foaming due to carbon dioxide gas at the time of curing, has excellent curability and storage stability, and further has a feature that there is little residual tack on the coating film surface. Thing and waterproofing material using it.

Claims (3)

(A) Prepolymer having two or more isocyanate groups at the terminal consisting of a reaction product of tolylene diisocyanate and polyoxyalkylene polyol, (B) polyphenylmethane polyisocyanate or its carbodiimide modified product, (C) (c1) at the terminal a urethane prepolymer having two or more isocyanate groups, (c2) is reacted with N-2--hydroxyalkyl oxazolidine consists urethane oxazolidine prepolymer having oxazolidine groups at the terminal obtained by the the (a) (B) Is a moisture curable urethane resin composition characterized by having an isocyanate equivalent ratio of 90:10 to 15:85. The polyphenylmethane polyisocyanate or a carbodiimide-modified product (B) thereof is a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate or carbodiimide-modified diphenylmethane diisocyanate . Moisture curable urethane resin composition. The waterproof material which consists of a composition in any one of Claims 1-2 .